In automated storage systems, for example, high rack storage facilities, transport pallets, preferably so-called wooden Euro pallets, are transported automatically by roller conveyors, chain conveyors, rack servicing devices and/or other devices, moved to the desired storage location of the storage system, and removed as needed.
It is known that the employed wooden pallets partially cause significant operational disturbances; in particular by using low quality wood material in the wooden pallets that are supplied from the outside to the storage system, the number and the severity of operational disturbances appear to be increasing.
Even when undamaged wooden pallets are introduced into the storage system, the load on the skids caused by the conveying equipment can lead to damage on the wooden pallets and thus to operational disturbances.
Low quality wooden pallets have generally also relatively strong deviations of their geometry relative to the nominal dimensions set by standards; this also may cause disturbances.
This has the results that, for example, in storage systems that only store their own wooden pallets, particularly expensive wooden pallets of select wood pieces are used. This solution cannot be employed in storage systems that primarily store pallets that are delivered by third parties.
Moreover, in many storage system there is the need to store also pallets with smaller major dimensions than the standard pallets (half pallets, quarter pallets) in a mix with standard pallets.
In order to avoid these problems, DE 42 42 472 A1 discloses a support structure for wooden pallets that is substantially comprised of a shell that is precisely dimensioned to match the bottom side of the wooden pallets. Into this shell the loaded wooden pallet is inserted before entering the storage system and removed again after leaving the storage system. This solution however has not found acceptance in practice.
Known automated storage systems require conventionally the use of pallets with skids, inter alia because of the employed roller conveyors. The use of inexpensive nesting pallets that generally do not comprise skids and therefore cannot be conveyed on roller conveyors is thus impossible.
Plastic pallets with skids that are not provided with special devices, for example, steel reinforcements, also generally cannot be employed in automated storage systems because the deformation caused essentially by creeping of the plastic material may cause operational disturbances. By means of complex auxiliary supports that additionally support the pallets across the bridged length, the problem of deformation can be solved.
At the same time, plastic pallets with skids are basically considered to be operationally safer than wooden pallets because of their geometric integrity and dimensional stability. Therefore, sometimes high-quality plastic pallets are used in automated high rack storage facilities. These expensive pallets are however subject to significant wear.